1. Field of the Invention
The present invention relates generally to hand tools and, more particularly, to a multi-purpose hand tool which is capable of being used for different tasks during commercial, industrial and residential construction, and to a scribing apparatus utilizing the multi-purpose hand tool.
2. Background Information
During the course of commercial, industrial and residential construction, various different hand tools are employed by construction workers. Generally, each hand tool is used to address one task. For example, in addition to the obvious requirement of a hammer and a saw, a carpenter/tradesman or homeowner also requires the use of a number of additional hand tools such as a combination square, a tape measure, a combination of tools to mark a piece of material which needs to be fitted against an uneven surface or to mark a door frame or a window frame for the installation of a door casing or a window casing, a compass to scribe cut lines for arcs and circles, and a utility knife or pencil sharpener to sharpen the point of pencils.
Traditionally, construction workers have maintained and transported one or more large boxes containing such single purpose hand tools to their work site, from which they draw the appropriate tool, as necessary. Having to stop and retrieve the appropriate single purpose hand tool and having to stock the various hand tools, however, is generally a great inconvenience, and costs a considerable amount of time, money and energy. Although it would be desirable, a construction worker cannot possibly keep one of each of the possible requisite hand tools in his or her work apron or pouch. Thus, because of the number of different tools which must be transported to the work site, and carried by the construction worker, a single hand tool which is capable of being used to address multiple tasks has been sought.
Several prior art devices are known which attempt to combine several hand tools into one device. However, applicant has no knowledge of any compact multi-purpose hand tool which is capable of being used to mark a piece of material which needs to be fitted against an uneven surface, mark door and window frames for the installation of door or window casings, and mark the cut line for arcs and circles, and which incorporates a pencil sharpener for sharpening pencils used in conjunction with the multi-purpose hand tool and a scale which may be utilized as a ruler to measure dimensions associated with the foregoing uses of the multi-purpose hand tool. Furthermore, the prior art devices are not sufficiently lightweight and compact to be easily stored in a construction worker's apron or pouch.
When marking a given piece of material which needs to be fitted against an uneven surface, the construction worker has the task of doing it in one single operation, thereby leaving no room for mistakes. This is typically done using a compass, set at a chosen measurement between a compass point and a pencil point. Use of the compass is not foolproof because of movement between points and the carpenter's inability to keep a steady hand and constant angle. This task can also be done using a block of wood, however, this does not provide accuracy to corners or badly out of shape walls.
When marking door and window frames for the installation of door or window casings, accuracy is of the utmost importance for appearance as well as functionality. Conventionally, a tape measure has been used to mark the window or door frame to the desired distance set back from the edge of the frame (e.g., ¼″ or ¾″). However, the tape measure is not very well designed to mark such small measurements without substantial difficulty. Other conventional methods of marking door and window frames for the installation of door or window casings involves the use of a combination square and the use of two connected pieces of square blocks. However, connecting pieces of square blocks is time consuming, and field conditions may require additional blocks of wood to be made up to accommodate different set back measurements (i.e., ¼ inch set back, ⅜ inch set back, ½ inch set back, etc.) which would require fabricating and connecting additional pieces of wood for marking the new set back measurement.
A compass is typically used in conjunction with a tape measure to draw circles. However, restrictions and accuracy apply with respect to the size of circles the compass can draw. Furthermore, not only is the compass not durable when mixed with tools of more durable quality but is difficult to use when drawing a circle beyond a certain diameter (e.g., 7 inches). Thus, while the compass is a very resourceful construction tool used primarily by highly-skilled construction workers, it often cannot be found when needed because of its small size and it becomes damaged easily which makes it difficult to draw a circle with precision.
Moreover, for the purpose of drawing circles of diameter sizes larger than permitted by conventional compass tools, two methods have been proposed. A first method involves the use of a piece of string which is selected of a length corresponding generally to the radius of the desired circle to be drawn on the material to be marked. One end of the string is connected to a fastener, such as a screw, which is fixed to a location on the material corresponding to the center of the circle to be drawn. The opposite end of the string is wrapped around a pencil at the desired radius point. The user then pivots the string and pencil around the center screw to draw the circle. However, such method results in imperfect arcs or circles due to the fact that consistent tension on the string is difficult to maintain.
In the second method, a user cuts a strip of material to a preselected length corresponding to a desired radius for the circle to be drawn. A pilot-hole (e.g., 3/6″ diameter) is then drilled at a location approximately one inch from one of the ends of the strip of material. The desired radius length is then measured and a pencil hole is drilled at the other end of the strip of material. The user then fixes a screw through the pilot-hole into the material to be marked at a position corresponding to the center point of the circle and rotates the strip of material and pencil around the center point, thereby drawing an arc or circle. However, the problem with this method is that any mistake in measurement or inaccuracy in drilling the holes will necessitate new holes being drilled by starting the process again or drilling as many holes as necessary to achieve an acceptably accurate result. This method is time consuming and increases the overall cost of construction projects.
The present invention overcomes many of the disadvantages inherent in conventional multi-purpose hand tools and with the necessity of using various different hand tools during commercial, industrial and residential construction. The foregoing and other objects of the present invention will become apparent to those skilled in the art in view of the description of the best presently known mode of carrying out the invention as described herein and as illustrated in the drawings.